Embodiments herein generally relate to label printing and more particularly to a structure that produces finished rolls of labels from cut sheets.
Label converting (printing, die-cutting, coating, etc.) is a large and healthy world-wide market. Label printing has traditionally been done by “analog” methods—mainly flexography, but also gravure and offset. However, in recent years, a number of digital label presses have become available. These presses were first based on electro-photography but more recently several ultraviolet (UV) inkjet label presses have been introduced.
Pressure-sensitive (PS) labels are by far the primary focus of digital label presses. A pressure-sensitive label can be a three-layer lamination consisting of label substrate, adhesive, and liner/backing media. The pressure sensitive laminate is typically purchased by the converter, who prints the labels, die cuts, and removes the waste trim from around the label. The fully converted and finished roll stock of labels is then sent to the end user. In the label machine, the labels are peeled off the liner by passing over a peel plate, and applied directly to, for example, a product container. Pressure-sensitive labels are used broadly in all market segments, and are a dominant component of the “prime label” market.
Analog methods such as flexography have relatively low run cost, but the setup costs, including flexography plate preparation, is expensive. Consequently, the analog methods are cost-effective for long runs but very expensive for short runs. The advantage of digital label presses is that they do not require plates and the setup costs are lower, so they are the preferred alternative for short run jobs.
However, the setup costs of current digital label presses are sufficiently high to make very short runs extremely expensive. For very short runs (e.g., 100 labels) of small labels, the setup costs to the end-user are almost 100% of the total cost, even for digital label presses. So there is only a small window of opportunity for the digital label presses, being limited at the short run end by setup costs, and at the long run end by the lower run costs of analog presses such as flexography.
One obstacle to significantly reducing the setup cost of digital label presses is the substrate changeover activity. Digital label presses are mostly roll-to-roll machines, since the finished labels are applied to the containers using roll-fed machines, and even manually applied labeling operations often utilize a dispenser, which requires a roll of labels. A typical label converter offers a large variety (dozens) of label substrates, including many types of coated and uncoated and metalized papers as well as white, clear and metalized films of biaxially oriented polypropylene (BOPP), polyester, vinyl, etc. In addition, each of these substrates can be provided with different types of adhesives. Consequently, although job management software facilitates batching jobs to reduce changeovers, substrate changes between jobs are common. And because these substrates are roll-fed, the changeover takes time and labor, in addition to idling the press and thereby reducing productivity.